1. Field of the Invention
This invention relates to railways and in particular to railroad grade crossings.
2. Brief Description of the Prior Art
In a conventional railroad grade crossing, wood deck panels are made to fill the space between the tops of the crossties and the top of the rails. The panels are installed over the ties outside the rails (called the field side) and between the rails (called the gage side). During installation, the wood deck panels are placed on the ties in predetermined locations, lead holes are drilled through the panels into the ties beneath, and drive spikes are driven through the panels into the ties, securing the panels in place. Usually eight drive spikes hold the deck panels in place on the ties against the forces generated by rail and vehicular traffic.
With the passage of time and traffic, the rail bed must be maintained at intervals of one to five years. Maintenance consists of replacing worn track parts, re-ballasting and re-aligning the track. At grade crossings, if the track is to be "maintained through" the crossing, the wood deck panels must be removed, and then replaced when the re-alignment is finished. Because the drive spikes are difficult to remove, the deck panels are often destroyed in the removal process.
Treated wood deck panels will last a long time in service, twenty years not being uncommon. Panels installed with drive spikes may develop adverse wear patterns over the years. Also the drive spikes may become raised above the deck surface causing a potential hazard to vehicle tires.
Since the life of the wood deck, if it is left in place, is substantially longer than the track maintenance cycle, many railroads will maintain the track up to each side of the crossing, but skip the crossing itself until the crossing deck is in such a condition that it must be replaced. Because crossings are short in length compared to the whole track, this minor deferred maintenance practice is tolerated in the interest of economy. However, as trains become heavier and faster, a higher degree of track maintenance is required, and the crossings must be repaired more often.
It is to provide an improved railroad crossing to which this invention is directed.